Simon Price, who has died of cancer aged 56, was a major and innovative figure in the study of the religious history of the Graeco-Roman world. In his book Rituals and Power (1984), he radically changed ideas about the worship of Roman emperors. Previously, such worship had been seen as a device imposed on the provinces by the new imperial regime of Augustus after the fall of the republic; both the reasons for its invention and for its acceptance by the provinces were read as wholly political in motivation, having no connection with any notion of "religion".

Simon used the epigraphic record of the Greek-speaking cities of Asia Minor, today western Turkey, which provide in some cases rich details of the organisation of rituals and festivals. By careful reading of this material, he was able to show that an essential role had been played by the leading citizens themselves through local initiatives, and that there was great variation in practice from city to city, not a single unified imperial cult. He concluded that the form of worship resulted through negotiation locally and with the authorities in Rome, producing a means of expressing, in religious terms, the new power structure with which the communities now had to cope.

Price and Peter Thonemann's The Birth of Classical Europe was driven by the role of memory in defining the ancients' sense of themselves and their own past

Controversially, Simon argued that it was a misconception to assume, on the analogy of Christianity, that the ancients had specific religious "beliefs", as opposed to a commitment to rituals of communication with the gods, which were central to civic and family life. The position has sometimes been misunderstood as implying that the religion consisted of ritual actions alone, without ideas, thoughts or commitment; but that was far from his conception, in which ritual was to be seen as "an embodiment of thinking".

Simon was born in London and grew up in Manchester, where his father was a canon at the cathedral and then bishop of Ripon. Simon explained that his interest in religion came from "growing up in an Anglican cathedral house". He was educated at Manchester grammar school and Queen's College, Oxford.

His early years as a researcher encompassed Oxford, where he was registered for the DPhil; University College London, where I supervised his Oxford thesis, and Cambridge University, where he held a junior research fellowship at Christ's College. From 1981 until his early retirement, he was fellow and tutor in ancient history at Lady Margaret Hall, Oxford, to whose students he became deeply devoted.

In 1985, he married the archaeologist Lucia Nixon; she and their two daughters, Elizabeth and Miranda, survive him. Lucia co-directs the Sphakia survey in south-western Crete, covering a large geographic area and a huge time span – prehistoric, Graeco-Roman and Byzantine-Venetian-Turkish, to 1900 – and concerning the relationship of humans to their environment over this long period of changing economic and social circumstances. Simon worked with the project in many capacities, particularly on the historical sources. The project fitted his own conviction that good history can only be written using all types of available evidence in combination.

Simon was a great man for collaboration: in his work over many years for the journals of the Roman Society; in running seminars and publishing jointly edited volumes, not least in the writing, with Mary Beard and me, of Religions of Rome (1998), in which we tried to set out a radically different vision of the role of religion in 1,000 years of Roman history. He found life, energy and creativity in areas where much earlier scholarship had detected little but emptiness and political exploitation. He also established a fine reputation as a supervisor of research students.

Simon's interest always lay not just in collecting information or sorting out facts, essential though both were to him, but also in pursuing an idea. His most recent book, The Birth of Classical Europe (with Peter Thonemann, 2010), while providing an excellent survey of events from Troy to the sack of Rome and beyond, is driven by the role of memory in defining the ancients' sense of themselves and their own past, and also in exploring conceptions of antiquity as remembered through successive periods of later European history.

Simon took early retirement when he was diagnosed with cancer in 2008 and used the time left to him – all too brief, but longer than had been feared at first – to impressive effect. Apart from work on the Sphakia survey, he completed the co-editing of a collection of essays, including one of his own; and gave a successful lecture on religious mobility in the Roman empire at the Collège de France in Paris, to be published next year.